Degreasing apparatus



Dec. 12, 1944. M. HELLER 2,364,976

DEGREASING APPARATUS Filed. Dec. 19, 1941 2 Sheets-Sheet l 2 sheets-Sheet 2 M. HELLER DEGREASING APPARATUS Flled Dec 19, 1941 Dec. 12, 1944.

Fig. 2.

M H 7 M Mp w W u z 5 M Q M Patented Dec. 12, 1944 DEGREASIN G APPARATUS Max Heller, London, England Application December 19, 1941, Serial No. 423,698 In Great Britain January 18, 1941 8 Claims. (01. 202-170) This invention relates to degreasing apparatus of the kind in which the articles to be degreased are subjected, while in an elongated perforated container or basket situated in an elongated degreasing tank, to the vapours of a grease-solvent such as trichlorethylene, perchlorethylene or the like.

An object of the invention is to devise a practical and efficient reflux condensing means for the vapour solvent whereby the articles, following their primary treatment with solvent vapour, will be cleansed or rinsed with the vapour condensate.

The attempt to achieve this object gives rise to difficulties. Firstly, there is the difficulty with a tubular condenser disposed above the basket of ensuring that the vapour condensate formed thereon will drip or flow from definite points. Secondly, in apparatus employing an elongated basket that turns about its long axis, there is the further difficulty of ensuring that the condensate falling on to the periphery of the basket will be caused to pass evenly into the interior of the basket along substantially, its whole length.

In order to overcome the first mentioned difficulty the invention provides, in degreasing apparatus of the kind hereinbefore set forth, a condenser disposed in the tank above the basket with its axis substantially horizontal and parallel to their long axes and having means that then automatically afford without further orientation of the condenser a constantly aligned row of drip points for solvent vapour condensed on its surface.

Preferably the condenser is constructed as a closely coiled or sinuously bent tube the lower points of the turns or bends of which automatically define a truly aligned row of drip points when the condenser is simply disposed in the degreasing tank above the basket with its axis substantially horizontal and parallel with their long axes. Any suitable coolant may be circulated through the coiled or bent tube to bring about condensation of the solvent vapour on its exterior surface. Alternatively, the condenser may comprise an externally finned tube, either with spaced, parallel, circumferential fins, or with a helically extending fin the lower points of which automatically define a truly aligned row of drip points when the tube is disposed as aforesaid.

By providing definite drip points for the solvent vapour condensate in the manner described, the condensate can be caused to fiow back into the basket so as to be uniformly distributed over its contents and ensure an efficient cleansing or rinsing of the same.

In an apparatus employing a basket rotatable about a horizontal axis the invention further provides, in combination with a condenser constructed and disposed as aforesaid, means to overcome the stated second difficulty, 1. e. means to ensure that the vapour condensate falling from the definite drip points of the condenser on to the periphery of the basket will assuredly enter the interior of the basket still in a distributed manner. The said means consists in forming rows of slots through the periphery of the basket, said slots extending parallel to its axis and the leading walls of the slots, in the direction of rotation of the basket, being tapered or inclined to guide the condensate towards and through the slots. The slots in each row may be staggered with respect to those in adjacent rows.

The invention is applicable both to closed degreasing tank apparatus and open degreasing tank apparatus.

Although reference has been made to a condenser it is to be understood that more than one condenser may be provided, for example two, each constructed and disposed in the manner described.

By way of example, a closed degreasing tank embodying one form of the invention is illustrated on the accompanying drawings and will now be described, only such parts being referred to as are necessary for a clear understanding of the invention.

Fig. 1 represents the tank in longitudinal section.

Fig. 2 represents a cross section through the tank in the plane marked II-II in Fig. 1.

Fig. 3 represents, on a larger scale, a fragmentary cross section of the perforated container or basket.

Fig. 4 is a fragmentary elevation of another form of condenser.

Reference i denotes the tank, whose lower part has a steam jacket 2, and 3 the tank lid or cloreflux condenser in the form of a helically coiled tube 8 whose ends are jointed, at 9, to a coolantinlet and outlet connection marked l and II respectively. As is readily apparent from Fig. l, the said condenser is carried by the lid 3 of the tank and is therefore displaceable outwardly with the lid from its normal operative position to enable the basket to be lowered into and raised from the tank. The connections I0, II are attached by flexible tubing, not shown, with the source of supply of coolant.

From Fig. 1 it will also be apparent that the lower point of each convolution or turn of the condenser tube 8 constitutes a definite drip point for solvent vapour condensate formed on the surface of the convolution or turn, and that the simple expedient of disposing the tube substantially horizontally assures a vertically aligned series of such definite drip points. It follows that in the use of the degreasing apparatus the condensate is caused to flow back On to the surface of the basket 6 in a uniformly distributed manner.

To ensure that the condensate falling uni formly on to the periphery of the basket 6 will be caused to pass evenly into its interior along substantially its whole length and be uniformly distributed over the contents of the basket, the perforations through the basket are in the form of rows of slots [2 (Fig. 3) extending parallel to its axis and the leading walls l3 of the slots, in the direction of rotation of the basket, are tapered or inclined to guide the condensate towards and through the slots. The slots in each row are preferably staggered with respect to those in adjacent rows.

Solvent vapour is admitted to the interior of the tank through the branch l4. Another branch 15 leads to an external condenser, not shown, for recovery of any solvent vapours displaced with air from the tank I at each cyclic operation.

The operation of the described apparatus is a follows:

The perforated basket 6, removed from the degreasing tank I, is packed with the articles to be degreased and is then inserted in the tank, whereafter the lid 3'is tightly closed. Thereby the reflux condenser 8 is disposed above the basket as shown in the drawings. Solvent vapour is now admitted, by way of the branch I4, into the interior of the tank I, and drives off the air through the branch l5. Any solvent vapour escaping with the air is recovered in the beforementioned recovery condenser. The branch I5 is then closed and solvent vapour is still admitted to the tank I while the basket 6 is rotated. Such vapour has access through the perforations I2 in the basket to the articles packed therein to bring about their degreasing. Solvent vapour reaching the upper part of the tank condenses on the surface of the coiled tube 8 through which coolant is circulated from the time of closing the tank lid. The condensate drips from the definite drip points afforded by the lower points of the turns of the tube on to'the perforated basket whence it passes uniformly through the perforations on to the articles in the basket. Thus the said articles, following their primary treatment with solvent vapour, are cleansed or rinsed with the vapour condensate. Finally, after withdrawing grease-laden solvent from the degreasing tank and recovering the solvent vapours, the lid 3 is swung open and the basket 6 is lifted out for removal of the cleansed articles and packing with a further batch of articles to be degreased, whereupon the described operation is repeated.

M The modified condenser shown in Fig. 4 comprises a tube 8a, through which coolant is circulated, having spaced circular fins 8b.

Reflux condensing means in accordance with the invention automatically affords a row of predetermined drip points for condensed solvent vapour when set up substantially horizontally, and this constitutes an advantage over the known reflux condenser in the form of a tube made with a row of so-called drip noses because with the latter it is necessary, not simply to set the tube substantially horizontally, but also to arrange that the radial plane of the tube through the apices of the noses is set truly vertical.

It will now be apparent that a reflux condenser in accordance with the invention virtually comprises a series of independent condensing elements combined to a unitary whole, at the deepest point of each of which elements the condensate collects automatically and from which the condensate then drops as required. Thereby a definite dropping row is formed-without any special constructional measures having to be taken to ensure such an aligned row and without having to ensure that the condenser is set up strictly horizontally in the degreasing apparatus.

Although in describing the invention reference has been made to a single reflux condenser, it is to be understood that more than one condenser may be provided; for example, two, each constructed and disposed in the manner described.

I claim:

1. In a degreasing apparatus of the kind in which articles to be degreased are subjected to the vapours of a grease-solvent, the combination of an elongated degreasing tank to be permeated by the said vapours, an elongated perforated container for the articles in the degreasing tank, and an elongated condenser disposed in the tank above the container with its axis substantially horizontal and parallel with their long axes, said condenser having means automatically affording without furtherorientation of the condenser a constantly aligned row of drip points for solvent vapour condensed on its surface.

2. In a degreasing apparatus of the kind in which articles to be degreased are subjected to the vapours of a grease-solvent, the combination of an elongated degreasing tank to be permeated by the said vapours, an elongated perforated container for the articles in the degreasing' tank, and a helically coiled condenser tube disposed in the tank above the container with its axis substantially horizontal and parallel with their long axes, the lower points of the turns of the condenser tube automatically affording without further orientation of the tube a constantly aligned row of drip points for solvent vapour condensed on its surface.

3. In a degreasing apparatus of the kind in which articles to be degreased are subjected to the vapours of a grease-solvent, the combination of an elongated degreasing tank to be permeated by the said vapours, an elongated perforated container for the articles in the degreasing tank, and a condenser comprising a sinuously bent tube disposed in the tank above the container with its axis substantially horizontal and parallel with their long axes. the lower points of the bends of the tube automatically affording without further orientation of the tube a constantly aligned row of drip points for solvent vapour condensed on its surface.

4. In a degreasing apparatus of the kind in which articles to be degreased are subjected to the vapours of a grease-solvent, the combination of an elongated degreasing tank to be permeated by the said vapours, an elongated perforated container for the articles in the degreasing tank, and a condenser comprising an externally finned tube disposed in the tank above the container with its axis substantially horizontal and parallel with their long axes, the lower points of the fins automatically affording without further orientation of the tube a constantly alignedrow of drip points for solvent vapour condensed on its surface.

5. Degreasing apparatus according to claim 1, the container being mounted in the tank for rotation about its long axis and having perforations in the form of rows of slots extending parlallel to that axis, the leading walls of the slots in the direction of rotation of the container being chamfered thereby to guide condensate dripping from the condenser on to the periphery of the container towards and through the slots.

7. Degreasing apparatus according to claim 3, the container being mounted in the tank for rotation about its long axis and having perforations in the form of rows of slots extending parallel to that axis, the leading walls of the slots in the direction of rotation of the container being chamfered thereby to guide the condensate on to the periphery of the container towards and through the slots.

8. Degreasing apparatus according to claim 4, the container being mounted in the tank for rotation about its long axis and having perforations in the form of rows of slots extending parallel to that axis, the leading walls of the slots in the direction of rotation of the container being chamfered thereby to guide the condensate on to the periphery of the container towards and through the slots.

MAX HELLER. 

